In recent years, steering wheels having a temperature adjustment function (heater and/or cooler function) have been proposed and put into practical use for automobiles and any other vehicles. For example, a structure in which a heater element is disposed on the outer side of a cored bar has been proposed. Examples of conventional steering wheels with a heater function include a steering wheel disclosed in Japanese Patent Application Laid-open No. 2007-153026.
For a steering wheel having a heater function, it is important to efficiently transfer heat to a steering outer cover. As disclosed in Japanese Patent Application Laid-open No. 2013-139203, a structure in which a framework is formed as the surface of a rim and a heater element is disposed on the framework has been proposed. The invention disclosed in the previously mention reference, however, may give a driver a hard touch feeling of gripping the steering wheel, and the driver may often feel uncomfortable. Further, the structure and its manufacturing steps are complicated due to the increased number of components and the cost is inevitably increased.
The present invention has been made in view of the problems as described above, and it is an object of the present invention to provide a steering wheel capable of minimizing an increase in cost due to addition of a temperature adjustment function.
It is another object of the present invention to provide a steering wheel capable of efficiently and uniformly transferring heat (heating energy, cooling energy) to a steering wheel covering.